Which statements are true? The transition state is the highest free energy that a reaction reaches during its progress from reactants to products. Enzymes alter the free energy of the transition state but not its chemical nature. High affinity binding of substrate by enzymes alters the equilibrium between reactants (substrates) and products. High affinity binding of substrate by enzymes can impede reaching the transition state. Steric and electrostatic interactions between the enzyme and substrate usually disfavor the ground state of substrate and favor the formation of the transition state. If ∆G‡(catalyzed) is less positive than ∆G‡(uncatalyzed) then the enzyme is enhancing the rate of the reaction. Low affinity binding of substrate by the enzyme must always lead to a slower rate of reaction compared to the uncatalyzed rate. There is no barrier to substrate binding to an enzyme, only to the chemical step.

Which statements are true? The transition state is the highest free energy that a reaction reaches during its progress from reactants to products. Enzymes alter the free energy of the transition state but not its chemical nature. High affinity binding of substrate by enzymes alters the equilibrium between reactants (substrates) and products. High affinity binding of substrate by enzymes can impede reaching the transition state. Steric and electrostatic interactions between the enzyme and substrate usually disfavor the ground state of substrate and favor the formation of the transition state. If ∆G‡(catalyzed) is less positive than ∆G‡(uncatalyzed) then the enzyme is enhancing the rate of the reaction. Low affinity binding of substrate by the enzyme must always lead to a slower rate of reaction compared to the uncatalyzed rate. There is no barrier to substrate binding to an enzyme, only to the chemical step.

Human Biology (MindTap Course List)

11th Edition

ISBN:9781305112100

Author:Cecie Starr, Beverly McMillan

Publisher:Cecie Starr, Beverly McMillan

Chapter3: Cells And How They Work

Section: Chapter Questions

Problem 8SQ: Enzymes _______. a. enhance reaction rates b. are affected by pH c. act on specific substrates d....

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Indicate whether each of the following statements about an enzyme active site is true or false. It is the location where substrate molecules are produced. It always has a fixed, rigid geometry. It always has a geometrical shape exactly complementary to that of substrate. It always accommodates several structurally related substrates. It is the location where substrate molecules are converted to product molecules. It always has a shape that has a degree of flexibility to it. It always accommodates only one specific substrate.
Which of the following is NOT true about enzymes? Enzyme inhibitors interact reversibly or irreversibly with an enzyme to alter its Km and /or Vmax values. Enzymes typically act under milder conditions of temperature and pH than non-enzyme chemical catalysts. Zymogens are the inactive precursors of enzyme. Nucleophilic groups can catalyze reactions through the transient formation of covalent bonds with the substrate. Transition state stabilization can significantly increase the activation energy for a reaction.
When the enzyme hexokinase binds to glucose and ATP it undergoes a conformational change. All of the following are true about this enzyme-substrate binding EXCEPT: The active site changes shape so that it binds more tightly to the substrates The substrates are optimally positioned for the reaction to occur The substrates become contorted or strained, which increases their reactivity The activation energy of the reaction increases
A transition-state analog— resembles the active site of general acid-base enzymes. is less stable when binding to an enzyme than the normal substrate. stabilizes the transition state for the normal enzyme-substrate complex. reacts more rapidly with an enzyme than the normal transition state intermediate. resembles the transition-state structure of the normal substrate in the enzyme-substrate complex.
Which of the following statements is false regarding an enzyme's ability to catalyse a reaction? an enzyme provides a reaction surface and a hydrophilic environment for the reaction to take place an enzyme binds reactants such that they are positioned correctly and can attain their transition-state configurations an enzyme allows the reaction to go through a more stable transition state than would normally be the case an enzyme can weaken bonds in reactants through the binding process
Which of the following statements is true about effect of substrate concentration on enzyme activity ? The rate of reaction increases as the substrate concentration increases up to certain limit at which the reaction rate is maximal (Vmax.) At Vmax, the enzyme is completely saturated with the substrate, At Vmax, any increase in substrate concentration don't affect the reaction rate. All of them
Please select all of the following statements that are true. Cofactors involve the use of vitamins to assist enzymes Competitive inhibitors bind to the same active site as the substrate. When the substrate binds to the enzyme the reaction rate increases. Non-competitive inhibitors can act as both inhibitors and activators.
Indicate whether each of the following statements about enzyme terminology is TRUE or FALSE. All conjugated enzymes contain a cofactor. An apoenzyme has both a protein and nonprotein part. Metal ions cannot be present in a cofactor. An apoenzyme is present in all holoenzymes. Simple enzymes cannot contain cofactors. A holoenzyme has both a protein and nonprotein part. Metal atoms are present in all conjugated proteins. A cofactor is present in some, but not all, conjugated enzymes.
Select the true statements regarding the position of participating regions of an enzyme. Within the active site of an enzyme, non-amino acid additions such as cations are in optimal positions to bind and hold onto substrates. Within the allosteric site of an enzyme, amino acid side chains do not react chemically with substrates. Within the active site of an enzyme, non-amino acid additions are in optimal positions to chemically react with substrates. Within the allosteric site of an enzyme, amino acid side chains are in optimal positions to bind and hold onto substrates.
Which of the following statements regarding enzymes and transition states is true? stabilization of the transition state must be less than stabilization of ES for catalysis to occur binding of substrate to an enzyme often causes strain, thus promoting transition state formation the transition state conformation of an enzyme catalyzed reaction is identical to the conformation seen in the uncatalyzed transition state formation of the transition state always assures that the reaction will proceed to product none of the above are true
Below which is false about enzyme and catalysis? O Catalytic residues interact with substrates and help substrates reach "transition state". Catalytic residues may be far away from each other in the protein sequence. Enzymes go through changes when binding to substrates, but the changes are always temporary. During catalysis, enzymes never form covalent bonds with substrates. O During catalysis, enzymes may serve as an acid or a base.
Each enzyme has a specific which is the reactant that the enzyme will act upon. Induced Fit Model of Enzyme Action: The substrate induces a more complete fit of the active site around it. Active site can lower an EA barrier by: ງ